Additive manufacturing of thermoplastic polymers (typically nylon) is well known. For example, fused filament fabrication (FFF), which is also commonly called plastic jet printing has been used to form 3d parts by using thermo-plastic filaments that are drawn into a nozzle heated, melted and then extruded where the extruded filaments fuse together upon cooling (see, for example, U.S. Pat. Nos. 5,121,329 and 5,503,785). Because the technique requires melting of a filament and extrusion, the materials have been limited to thermoplastic polymers (typically nylon) and complex apparatus. In addition, the technique has required support structures that are also extruded when making complex parts that must survive the elevated temperature needed to form the part, while also being easily removed, for example, by dissolving it.
Selective laser sintering or melting (SLS or SLM) has been used to make 3d parts by selectively sintering powders in a bed of powder (see, for example, U.S. Pat. No. 5,597,589). In this method, a bed of powder maintained at elevated temperatures is selectively sintered using a CO2 laser. Once a first layer has been sintered, a further layer of powder is metered out and the selective sintering repeated until the desired 3d part is made. Since the powder must be sintered or melted, SLS has been limited by the need for complex apparatus and use of thermoplastic polymers with very particular characteristics to allow for sintering without warping, slumping and achieving desired fusing particularly between layers. This generally has limited the applicability mostly to polyamides (i.e., nylon) or composite powders containing nylon.
Stereolithography (SLA) or photosolidification has also been used to make polymeric parts (see, for example, U.S. Pat. No. 4,575,330). SLA builds up successive layers from a photocurable resin contained in a vat using UV laser. The part being manufactured is supported by a platen within the vat which moves down as each layer is photocured to form the part. Just as for SLS and FFF, SLA is limited to particular photocurable polymeric resins and requires complex apparatus to form the parts.
It would be desirable to provide an additive manufacturing method and parts made therefrom that avoid one or more of the problems of the prior art such as those described above. Likewise, it would be desirable to provide an additive manufacturing method, material for use in such a method and parts that have elastomeric properties without heating or irradiating the material used to make such a part.